1. Biological control (biocontrol) of invasive alien plants is a widely utilised weed management tool. Prospective biocontrol agents are typically assessed through host-specificity testing and pre-release efficacy studies performed in quarantine. However, rearing of the potential biocontrol agents and/or test plants is often difficult or impossible under quarantine conditions. Moreover, practitioners may attain laboratory-artefacts in quarantine, which may result in the potential agent being needlessly rejected. Field-based studies in the weed’s indigenous distribution could overcome...